| Wheel/rail is one of the core components of rail transit.Reasonable and scientific maintenance has a key effect on ensuring operational safety and reducing operating costs.Wheel/rail interface friction management is a key technical content of wheel/rail system operation and maintenance.Designing wheel/rail interface friction management system and building key functional modules can provide important support for wheel/rail interface friction management target selection and friction management applications.In this paper,the demand analysis and overall design of the wheel/rail interface friction management system were carried out firstly,and the wheel/rail interface state evaluation module and wheel wear prediction module were constructed.Based on the constructed modules,the selection analysis of wheel/rail interface friction management targets under different vehicle speeds and curve radii was carried out,and the wheel wear law in dry,water and oil conditions was predicted and analyzed.Preliminary suggestions for target selection and application schemes of wheel/rail interface friction management were proposed.The main conclusions of this paper are as follows.(1)The analyses of the business needs,functional requirements,and data demand of the wheel/rail interface friction management system were completed.The overall design of the system was proposed,including system design goals,system architecture design,system function design,system interface design,and construction of the wheel/rail interface state evaluation module and wheel wear prediction module.(2)Under 400 m radius curve,when the vehicle speed was less than 120 km/h,the optimization of the friction management target of top rail was more effective than the gauge face.And when the vehicle speed was 40 km/h,the rail side friction management target was recommended greater than 0.10 to avoid the increase in the friction coefficient of the rail top causing the wheel/rail attack angle to be too large.When the vehicle speed was 140 km/h,the management target of the friction coefficient of the rail top was recommended to be 0.30,thus the wheel/rail lateral force was relatively low.The wheel load reduction rate exceeded the safety limit value of 0.65,and the vehicle speed of the vehicle should be reduced.(3)When the curve radius is less than 800 m,reducing the friction coefficient of the gauge face can reduce wheel/rail wear,and reducing the friction coefficient of the top rail can improve the driving safety of the vehicle,it is recommended that the rail side friction management target be 0.10～0.20,and the rail top friction management target be 0.30～0.45.When the curve radius is greater than 800 m,reducing the rail top friction management target can reduce wheel/rail wear.It is recommended to coat the rail top with friction modifiers.At the same time,in order to avoid the lateral acceleration from exceeding the safety limit,the rail top friction management target should be greater than 0.30.(4)In the multi-curve section,the first wheelset of each bogie has the most severe wear and should be used as the key object of wheel/rail interface friction management.Under dry conditions,with the increase of running distance,the phenomenon of wear concentrated on the wheel flange becomes more and more serious,it was recommended that the gauge face to be lubricated with oil or grease,and the friction coefficient should be controlled within the range of 0.10 to 0.20.At the same time,there is eccentric wear on the wheel flange of No.2wheel,so the lubrication frequency and lubrication amount of No.2 wheel could be appropriately increased.Under dry conditions,the wheel wear tends to be faster and then slower with the increase of the running distance.The friction management of the wheelset in the early stage of wear should be focused on.Under the water or oil conditions,the wheel wear depth and wear growth rate were both small,it was suggested to use friction modifiers with water resistance and adhesion property. |
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